Telephone-exchange system.



.l. L. WRiGHT,

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED MAY18, 190s. RENEWED DEC.24. 1912.

Patented Apr. 1915.

2 BHEETIS-BEEBT l.

l. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

A'PPLICATION FILED MAY 18. 1905. RENEWED 050.24.19x2.

I 1 1 3%SQ'8Q atented A111. 6,1915.

2 SHEETS-SHEET 2 g] n uento'a Witnesses J a ZZZ fiw S and S whichcontrol the vertical and rotary magnets O and O remain the same. Theprivate relay D controlling the side switches remains unchanged. Inplace of the back release relays, which in the Strowger system are tiedto the trunk wires 5 and 6, I have substituted the retardation coil Sand the relay S". This relay S upon becomingenergized when the calledsubscriber answers, attracts its armature and disconnects the ringingrelay. The relay G is connected in place of the ringing relay K andcontrols it when energized. In the branch of the ringing relay K whichordinarily is connected directly to battery, I have inserted aninterrupting machine J, which alternately opens and closes the circuitof the ringing relay K when the relay G is energized. I have also'addedthe two foot springs 2 and 2' controlled by the spindle Z for thepurpose of disconnecting the relay G when the switch assumes its normalposition in case the called party does not answer.

The operation of my system is as follows: Referring now to Fig. l, thesubscriber at station A desiring to make a call removes his receiver,closing the circuit of the relay S at central. The relay S becomingenergized attracts its armature and closes the circuit of the relay S bythe following path: battery B, 20, 19, 8, s, 11, S to ground. The relayS" becoming energized closes the contacts s and 8 thereby completing thecircuit of the relay S'.- The relay S becoming active connects ground toone terminal of the relay S by the following path: ground, s 5 13, towinding of S The relay S being sensitive is readily responsive to anymakes and breaks of the subscribers line such as caused by his sendingdevice when making a call. The relays S and S are made sluggish and whenonce energized will keep their armatures attracted while impulses arebeing sent in and the contacts 8 and s of the relay S are making andbreaking. The relay S is affected slightly by these makes and breaks,but the relay S being controlled by the relay S is not affected in theslightest. As soon as the subscriber has removed his receiver and startsto send in his number with his sending device, which I have forsimplicity represented by the push button P, the relay S becomesresponsive. This relay, making and breaking the contacts 8 and s closesthe circuit of the relay S by the following path: battery B, 20, 19, s,8 18, S 13, 8 s to ground. The relay S becoming energized closes thecircuit of the relay S which in turn closes the circuit of the relay S.These three relays S S and S remain energized or active so long as a setof impulses are being sent in affecting the relay S. It will of coursefollow that the relay S is slightly affected by the making and breakingof the contacts 8 and s and the relay S is less affected by these makesand breaks, while therelay S is not affected in the least.

Having described how these various relays are operated and controlled, Iwill now show how the various impulses are transmitted to the connectorswitch shown in Fig. 2.

The subscriber, after removing his receiver, proceeds to send in thefirst digit of the desired number by manipulating the push button P. Therelay S, being responsive to these impulses, makes and breaks itscontacts corresponding to the number of impulses sent in. The set ofrelays S S and S become energized while the relays S and S becameenergized the instantthe subscriber removed his receiver. The relay S inFig. 1 repeats the impulses to the relay S, Fig. 2, by the followingpath: battery B, 20, 19, 8', 3 3 8 2-3, 3, S to ground. The relay Soperating, closes the circuit of the vertical magnet O by the followingpath: ground, s, s, 30, (Z, d, 31, F, 40, O, 41, 45 to battery B. Theoperation of the magnet 0 causes the spindle Z carrying the wipers w andw to step up vertically bringing the wipers opposite a row of contactscorresponding to the number of impulses sent. After this set of impulseshas been sent in, there is a momentary or prolonged closure of the lineand the relay S remains energized, opening thecontacts s and sdisconnecting the set of relays S S and S The dei nergizing of this setof relays which drop back in one, two, three order, allows an impulse tobe sent in over the rotary side of the trunk to the relay S by thefollowing path: battery B, 20, 19, 8, s 14, 8 s, 15, s s 24, 4, S toground. The relay S becoming energized, closes the circuit of theprivate relay D as in the ordinary Strowger system, which in turn causesthe side switches F, F, F and F to move one point This movement of theside switches disconnects the vertical magnet O and in its placeconnects the rotary magnet 0. It also connects the test relay X to thetip wiper w by the following path: 46, F 32. (l d 34, 35, X, 36, 33, 45,to battery B. The subscriber now sending in the second set of impulsesof the desired number, operates the relay .8 which, as before, closesthe set of relays S S and S and transmits the impulses over the verticalside of the trunk operating the relay S which now in turn operates therotary magnet O causing the spindle Z to rotate and carry the wipersopposite the contacts leading to the desired line. After this second setof impulses has been sent in. the relays S S and S become disconnectedand an impulse is sent in over the rotary side of the trunk incenseoperating the relay 5 which upon closing the circuit of the privatemagnet D causes the side switches 1*, T, E 1, and F to make another stepdisconnecting the rotary ina net 0 and in its place connecting the relayG. During this momentary impulse over the rotary side of the trunk, thetest relay X is connected to the tip wiper w by the closing of thecontacts d and d If the called line was busy, this relay would becomeenergized and close the circuit of the release magnet X and restorethe-switch to its normal position. While ll have shown the test relay Xas applied to the sleeve wiper w, I am not limited to this specificconnection for releasing the switch in case the called line isbusy. Itis obvious that the restoration of the switch under such conditions maybe secured in a number of other ways, as for instance by means of athird wiper and cooperating stationary contacts arranged in the mannershown in the Keith and Erickson Patents Nos. 8 l5,321- and 815,176,previously referred to. Taking it forgranted that the called line isidle, the called-subscriber-sends in a third set of im pulses, or asingle impulse will answer the purpose, aliecting the relay G which,becoming energized, locks itself through the contacts .9 and 'g. Thisrelay remaining energized closes the circuit of the ringing relay K in 1series with the interrupting machine J. This relay becoming energizedand deenergized connects and disconnects generator current to the calledsubscribers line, ringing his bell alternately. The called subscriberupon removing his receiver completes the ci-rcuit'of the relay S whilethe relay is momentarily 'denergized. This happens. when the {pen orwiper of the interrupting machine is resting on the insulated portion.ing energized-opens thecontacts--s and 8 disconnectingthe relay G whichin turn cuts off the ringing relay K, thus preventing ringing current'from flowing over the line after the called subscriber has answered.

At the end of-the conversation, the ca-ll ing subscriber hanging up hisreceiver deenergizes the relayS and its armature falling backdisconnects the relay 8*, but before the relay S can-become deenergi-zedon account ofits being sluggish, the circuits of the relays S, S and Sare closed through the contacts sand 8- N ow by the time this second setof *relays has becomeenergized, the relay S has become deenergized andthe relays S S and S begin todrop 01f in one, two, three order, therelay S 'firstand the relay S last. pulse is placed on number 3 side ofthe trunk by the following path: battery B, 28, s ",--s, 22, s", s,-23-to wired A similar impulse is placed on number 4 side of the Therelay S becom- During this interval an im" trunk through the contacts 8and s. This impulse being placed simultaneously on both trunk wires,operates the relays S and S which in turn closes the circuit of thetestrelay X by the following path: ground, 8, s 35, X, 36, 33, 4-5 tobattery B. This test relay closes the circuit of the release magnet Xwhich restores the switch and all its parts 'to the normal or idleposition. If the called subscriber has not answered his telephone, therelay S would not have become energized and the relay G would remain ina locked position. The foot springs 2 and z are provided to meet thiscontingenoy so that even if the called party does not-answer, thecircuit of the relay G is opened when the switch is restored.

lit -will-be seen that T have formed two sets or groupsofrelays, one setof which is controlled directly by a single relay and the other set bythe joint action of the single relay and the first set. This combinationallows me to clifierentiate between the various-setsof impulses sent inover the subscribers line-to operate the switching mechanism and'torestore the same to normal position after the calling party has hung uphis receiver.

Having thus described my invention, what I claim and desire to secure byLetters Patent'is:

1. In a telephone exchange system, the combination with-aplurality ofsubscribers stations having impulse senders and a central stationprovided with an extension circuit, ofswitching-mechanism at the centralstation in the extension circuit controlling the continuity ofthesubscribers lines as between subscribers, impulse transmitting meansforthe rotary'sideof the extension, impulse transmitting means-tor theverti cal side of the extension, said impulse transmitting means for thevertical side of the extension controlling both the rotary and verticalimpulses, releasing mechanism for said switching mechanism, and meansfor controlling the same.

2. In a telephone exchange system, the combination with a switchingcircuit, switching mechanism at the terminus thereof, impulsetransmitting means for the vertical vside of the circuit, impulsetransmitting means for the rotary side of the circuit, controlling meansfor both the Vertical and rotary sides of the circuit, said controllingmeans acting-in conjunction with the vertical impulse transmitting meansto control the rotary impulse transmitting means, releasing mechanism,and means comprising a ci) the vertical and the rotary, impulse trans:mitting means and controlling means for operating said releasingmechanism.

3. lin a telephone exchange system, the combination with a switchingcircuit, switchin mechanism at the terminus thereof, impu lsetransmitting means for the vertical side of the circuit, controllingmeans for both the vertical and rotary s ides of the circuit, saidcontrolling means acting in conjunction with the vertical impulsetransmitting means to control the rotary impulse transmitting means, aplurality of sub-;

combination with a plurality of subscribers lines and stations havingimpulse senders and a central station containing an extension circuitfor each line, and switching mechanism at the terminus thereof, of a setof relays for sending the vertical impulses to the switchingmechanism, aset of relays for sending the rotary impulses for the switchingmechanism, and a controlling relay acting in conjunction with thevertical relay through its back contact to control the rotary relays.

5. In a telephone exchange system, the combination with a plurality ofsubscribers lines and stations having impulse senders and a centralstation containing anextension circuit for each line and switchingmechanism at the terminus thereof, of a set of sluggish relayscontrolling the vertical impulses to the switching mechanism, a quickacting relay in the set for operating said sluggish relays, a set ofrelays for transmitting the-rotary impulses to the switching mechanism,said quick acting relay of the vertical set controlling in combinationwith the sluggish relays the action of the relays .for' the rotaryimpulses, releasing mechanism, and means comprising the vertical'androtary relays and the nick acting relay for operating said releaslngmechanlsm when the subscriber hangs up his receiver.

6. In a telephone exchange system, the combination with a plurality ofsubscribers lines and stations and a central station containing anextension circuit for each line and switchin mechanism, a set of rela sat the centra station, means at the su scribers station for controllingthe relays at the central station whereby vertical impulses are sentover the circuit to the switching mechanism, another set of relays atthe vcentral station acting upon the release of the means at thesubscribers station to send a rotary impulse to the switching mechanism,releasing. mechanism, and means for controlling the releasing mechanism.

7. In atelephone exchange system, the

combination with a lurality of subscribers" 8. In a telephone exchangesystem, a plu-.

rality of subscribers stations provided with impulse senders, a centralstation provided with an automatic switch having vertical and rotarymovements, a sensitive repeating relay at said central station, two setsof transmitting relays arranged to control the automatic switch, thefirst set ofsaid relays remaining energized throughout conversa tion,the second set remaining energized only during the transmission of theimpulses from the repeating relay.-

9. In a telephone exchange system, sub,- scribers lines provided withimpulse sending devices, a central station having an automatic switchingmechanism, a repeating relay, two independent sets of relays controlledby said repeatin relay for operating said automatic switc, and meansactuatedby the denergization of both sets of relays to eflect thedisconnection and restoration of said switch to normal.

10. In a telephone exchange system, sub- 7 scribers lines provided withimpulse sending devices, a central station provided with an automaticswitch for interconnecting said lines, said switch having vertical androtary movements, two independent sets of impulse transmitting relaysarranged to transmit vertical and rotary impulsesto the automatic switchthereby effecting a talking connection, said sets of relays operating atthe end of the conversation to cause a simultaneous vertical and rotaryimpulse to be sent 'to the releasing mechanism for eifectin adisconnection of the talking circuit an a restoration of the parts totheir normal condition.

11. In a telephone exchange system, a plurality of substations, aplurality of automatic connective switches and circuits forinterconnecting the same, means for originating and directing impulsesto the switches to effect desired connections, test circuits associatedwith certain of said switches and individually closed in response to aspecial testfimpulse, automatic ringing means also associated with saidswitches and compris.

inga ringing relay having a circuit par-

